Looking at those photos, I reckon that's mostly dry snow. On the continent it gets proper cold and you get a very different kind of surface to the usual British freeze/ thaw/ freeze wet slush over ice horror. We had a really cold spell locally a couple of years back with about 4inches of snow. I rode a ten mile stretch of canal towpath and the difference in surface was a revelation, more like crisp fine sand than what I have been used to think of in the damp south west, as 'snow' Studs not necessary, tyres were the almost slick Big Apples, and the ride, apart from a few squirrelly bits over some frozen mud ruts, was entirely slip free.